21011221202220 has 120 divisors (see below), whose sum is σ = 65968514189424. Its totient is φ = 5598271511424.

The previous prime is 21011221202203. The next prime is 21011221202249. The reversal of 21011221202220 is 2220212211012.

It is a happy number.

21011221202220 is a `hidden beast` number, since 2 + 10 + 11 + 221 + 202 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21011221202193 and 21011221202202.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3540367 + ... + 7386246.

Almost surely, 2^{21011221202220} is an apocalyptic number.

21011221202220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011221202220 is an abundant number, since it is smaller than the sum of its proper divisors (44957292987204).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011221202220 is a wasteful number, since it uses less digits than its factorization.

21011221202220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10927821 (or 10927810 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21011221202220 its reverse (2220212211012), we get a palindrome (23231433413232).

The spelling of 21011221202220 in words is "twenty-one trillion, eleven billion, two hundred twenty-one million, two hundred two thousand, two hundred twenty".